Opioid receptors (ORs) mediate the actions of morphine and morphine-like opioids, including most clinical analgesics. Three molecularly and pharmacologically distinct opioid receptor types have been described: δ, κ and μ. Furthermore, each type is believed to have sub-types. All three of these opioid receptor types appear to share the same functional mechanisms at a cellular level. For example, certain activation of the opioid receptors causes inhibition of adenylate cyclase, and recruits β-arrestin.
The delta opioid receptor (DOR) has long been of interest as a target for potentially non-addictive treatments for a variety of CNS disorders. Recent evidence suggests that DOR activation may be beneficial in the treatment of migraine, neuropathic pain, Parkinson's disease, depression, anxiety and several other indications. However, some DOR agonists have caused seizure in preclinical species, hindering the development of selective drugs targeting the DOR. Thus there is a need to identify a DOR modulator for the treatment of these and other conditions. The present embodiments described herein fulfill these needs and others.